package com.smartandroid.sa.sql.util;

/*
 * Copyright (C) 2014 Markus Pfeiffer
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;
import java.io.InputStream;

public class Tokenizer {

	private final InputStream mStream;

	private boolean mIsNext;
	private int mCurrent;

	public Tokenizer(final InputStream in) {
		this.mStream = in;
	}

	public boolean hasNext() throws IOException {

		if (!this.mIsNext) {
			this.mIsNext = true;
			this.mCurrent = this.mStream.read();
		}
		return this.mCurrent != -1;
	}

	public int next() throws IOException {

		if (!this.mIsNext) {
			this.mCurrent = this.mStream.read();
		}
		this.mIsNext = false;
		return this.mCurrent;
	}

	public boolean skip(final String s) throws IOException {

		if (s == null || s.length() == 0) {
			return false;
		}

		if (s.charAt(0) != this.mCurrent) {
			return false;
		}

		final int len = s.length();
		this.mStream.mark(len - 1);

		for (int n = 1; n < len; n++) {
			final int value = this.mStream.read();

			if (value != s.charAt(n)) {
				this.mStream.reset();
				return false;
			}
		}
		return true;
	}
}
